Compressor governor



N. A. CHRISTENSEN Mmh 5, 1940.

` COMPRESSOR GOVERNOR 1 m @MHS Y .m f1 5 t TJ lll Y .r lllll m ww.. l 2 O Filed Jan. 7, 1939 INVENTOR FZ7] was HC42/neues# ATToRNl-:

March 5, 1940.

N. A. CHRISTENSEN COMPRESSOR GovEENoR Filed Jan. '7, 1939 2 Sheets-Sheet 2 Patented Mar. 5, 1940 UNITED 'sTATlzs [PATENT OFFICE COMPRESSOR GOVERNDB Niels A. Christensen, South Euclid, Ohio Application January 7, 1936, Serial No. 57,930

Claiml.

This invention relates to new and useful improvements in mechanism for controlling the operation of air compressors whereby the latter is rendered inoperative to compress air upon a 5 maximum pressure being created in a reservoir,

or'to automatically render the compressor operative to further compress air whenever the pressure in a reservoirdrops below a determined amount.

- An important object of the .invention is to 'provide a governor control which, while being extremely sensitive, is more positive in preventing the governor from becoming accidentally switched prematurely from "Off to On position, due to vibration incident to the apparatus. More particular1y,.the arrangement is such when the gov.- ernor retains the inlet valve of the compressor open, the lever arm of the latch is shortened whereby the associated spring has maximum strength in such position to hold the inlet valve against accidental closing due to vibration.

' Another object of the `invention is to provide the governor with cooperating latch and trigger mechanism, each of which possesses inclined portions for retaining the inlet valve either open or closed, and which inclined surfaces may be varied without affecting the spring tension of the latch.

Another object of the invention is to provide a structure in which the travel of the governor trigger is sufficient to cover the range of travel required in bothsingle and twin compressors so that one type of governor will serve for both types of compressors.

Still another 'object of the invention is to provide a governor control which is less expensive in construction due to the major portion of the parts being constructed from simple stampings.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings forming a part of the application and wherein like numerals are employed to designate like parts throughout the several views,

Fig. 1 is a vertical section through a portion of an air compressor with its associated governor mechanism illustrated in position whereby the compressor is operative to compress air.

Fig. 2 is a similar view with the governor illustrated in a position for retaining the inlet-valve of the compressor open whereby the compressor will not function to compress air,

Fig. 3 is an enlarged fragmentary section taken' on the line 3-3 of Fig. 1,

(ci. 23o-s0) Figs. 4 and 5 are corresponding vertical sections taken on the lines 4-4 and B--li of Fig'. 1, Figs. 6 and 7 are vertical fragmentary sections taken along the lines S-Sand 1-1 of Fig. 1,

Fig. 8 is an end elevation of the governor c'on- 5 trol illustrating its application to a twin cylinder compressor,

Fig. 9 is a side elevation of a modliled form of the governor constructed from stampings,

Fig. 10 is a side elevation of a portion of the 10 compressor with its associated governor control villustrating the manner of mounting the governor on the compressor,

Fig. 11 is a top elevation thereof,

Fig. 12 is an end elevation of the same illustratl5 ing more clearly the means for detachably retaining a cover or closure over the governor mechanism.

Referring now more particularly to the drawings showing two embodiments of the invention', 20 for the sake of illustration rather than limitation, an air compressor is designated by the letter C having an outlet valve O, connected in any suitable way to a compressed air reservoir, vnot shown, and aninlet valve I in communication 25 with the atmosphere. This inlet valve includes, in the present illustration, a leaf spring valve body, preferably of Swedish blue steel mounted i so that it is normally seated or closed as shown in Fig. 2 by its own inherent resilience and opens 30 under the intake of air through the inlet valve. Of course, other types of inlet valves may be employed which are normally held seated. When in this position, a downstroke of the compressor piston' automatically sucks in air through the $5 automatically opening inlet valve I. Upon the. compressor stroke of the compressor piston, thisl inlet valve closes while the outlet valve automatically opens and permits the compressed air to iiow through suitable piping to a, reservoir. This 40 'reservoir pressure is measured and maintained at a maximum pre-determined amount by a pressure responsive medium indicated in its entirety by the letter P, which in turn controls the position of the governor mounted upon a platform I3 45 suitably formed or fastened to the removable head I4 of the compressor cylinder. It will of course be understood that the operation of the inlet and exhaust valves is entirely automatic, the rush of air past these valves in both directions 50 causing the valve to move in the direction of the air current. The inlet valve therefore must be positively retained in open position when it is essential for the compressorto idle and no longer furnish compressed air to the reservoir or other suitable apparatus. In the present illustration, this is accomplished by a valve rod Il extending through the compressor head and support I3 to 'be yieldingly suspended by a hairpin spring I3 from pin or rod 5I of a governor latch I1 which will be presently described more fully.

The pressure responsive chamber which is connected with the compressed air reservoir at all times is provided with a pressure responsive diaphragm or piston I3 connected to a rod I3 normally urged downwardly to compress the bellows diaphragm I3 by a coil spring 2li surrounding the rod. The upper end of this rod I9 is pivotally connected to the intermediate portion of a trigger 2| formed from an inverted U-shaped stamping having its side walls 22 straddling a post 23 rising from the support I3. This support as will be noted, overhangs the side of the compressor and from it is suspended the pressure responsive casing P. Extending through this post 23 and the two side walls 22 of the trigger is a headless pivot pin 24 of uniform diameter throughout as best seen in Fig. 3; the pivot pin being prevented from accidental displacement by means of an inverted U-shaped stamping 25 of lighter gauge having its side walls 29 straddling the trigger as illustrated and xed against accidental displacement therefrom by an elongated cotter pin F extending through aligned apertures in the depending side walls of both U-shaped stampings. 'I'his member or saddle 25 also has its sidewalls engaging the ends of a pin 21 which is mounted transversely in both side walls 22 of the trigger and passes through an enlarged circular opening 23 provided in a lug on plate I3 whereby vertical movement of the trigger in both directions is limited by the pin 21 engaging the top or bottom of this enlarged opening. The free end of the trigger is provided with an anti-friction roller 29 to roll upon inclined faces 33 and 3| of one arm of a bell crank latch 32 pivoted by a transverse pin 33 in the free end of a valve actuating member 34. This member 33, as best appreciated from Fig. '1, is also formed from an inverted U-shaped stamping having -its side walls 35 provided with registering apertures to receive the ends of a transverse pivot pin 36 mounted in a post 31 rising from the support I3. The arch portion of this stamping is provided with an opening 33, into which extends the. upper end of a stop pin 39 carried in a socket in the upper end'of post 31. In order to prevent accidental displacement of both of these pins, the actuator 35 is straddled by an inverted U-shaped stamping I0 of lighter gauge whereby the top or bridge of this stamping prevents accidental displacement of pin 39, while its two side walls which overlap the corresponding walls of the latch of the actuator 34 confines the pivot pin 36 to preclude its accidental displacement. From the top of stamping 43 is struck an upwardly projecting lug 4I to which one end of acoil spring 32 is attached; the other end of the springA being connected to the upper bifurcated free end of the latch 32 by means of a pin 53 extending transversely across this-bifurcation and around which one end of the spring is hooked.

A stamped metal hood I3 protects the governor mechanism 'from extraneous matter and is detachably clamped upon the support I3 by means of either bolts M shown in Figs. 1 and 2 extending through the top of the hood and threaded into the support I3, or by means of a spring clip 35 rotatably mounted at the upper end of a post 33 threaded into the support I3 as shown in Figs. to 12 inclusive. The free end of the spring clip 43 is provided with a depressed portion adapted to seat in a corresponding depression in the top of the hood 43. springing the clip and swinging it on its pivot will disengage the hood or cover thereby permitting it to be removed for 5 ready accessibility to the governing parts.

Notation of the fact that incline 33 of the trigger 2i engages the latch 32 farther from the pivot pin 33 when the valve rod I3 is disengaged from the inlet valve and the latter is functioning `i0 normally, than when the trigger engages the upper inclined surface 3l of the latch 32 when the inlet valve is held open, will lead to an appreciation of the fact that the spring 32 in the latter position of the latch has greater strength and therefore there is less likelihood of the governor mechanism being accidentally tripped to release the inlet valve to closed operating position. Obviously, it ls essential to positively retain the inlet valve open so that the compressor idles and draws air idly past the valve and exhausts it on the compression stroke to the atmosphere without discharging it through the outlet valve O into the reservoir which is already loaded to capacity when the parts assume the position shown in Fig. 2, and when the lever `arm of latch 32 is shortened considerably from the eifective lever arm when the trigger 2| engages the lowerincline of the latch as shown in Fig. 1. When the valve operator 34 and latch 32 are in the posi- 30 tion shown in Fig. 1, the stop pin 33 engages the, forward end of opening 33 to limit upward swinging movement of the valve actuator 3l, and when the parts are in the position shown in Fig. 2, this stop pin 33 engages the rear end of the opening to limit the downward movement of the valve actuator.

When the mechanism is applied to a twin cyl` inder compressor, it is only necessary to extend the transverse rod 5I to which the hair springs 40 I8 are connected so that a valve operating rod I5 may be associated with each end thereof and both valves operated simultaneously from the governor' mechanism.

In Fig. 9 is shown a slight modidcation of the governor mechanism wherein the parts corresponding with the foregoing modification are designated with corresponding numerals employ--IJ ing prime coefilcients. Howeverl instead of the valve actuator 3l' being disposed horizontally, it 50 is arranged substantially vertically and is provided with a laterally extending stop pin 33 to engage the upper end of latch 32' to limit its upward vertical swinging movement about pivot 33. Again, the valve actuating rod I5' is pivot- 65 ally connected to the intermediate portion of latch 32' by means of a link 3l pivotally connected at one end of the latch and at its opposite-end to the upper end of the valve rod I3'.

vIn addition, the coil spring 42 is connected at do one end to the upper end of the stamping 3l' and at its other end to an extension of the post 23' as shown. However, it will be apparent that simple stampings, as in the preceding embodiment may be employed for the governor control and a saving in the cost of production over the types heretofore known.

In the modiilcation shown in Figs. 1 and 2, ready accessibility and replacement of the various parts can be achieved by simply removing the cotter pins F and removing the saddles 23 of the trigger and 43 ofthe valve actuator for exposing the various pivot pins whereby the parts may be readily taken apart and put together.

It will be understood that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In combination with a compressor having an inlet valve adapted to be held in open position against spring tension and rush of air, or permitted to function normally, a pivoted valve actuator mounted on the compressor and having a valve rod engageable with the valve to hold the same open, and a spring pressed latch pivoted on the actuator and engaged by said trigger at a point nearer the pivot of the latch when the valve is held open, than when the valve is in normal closed position.

2. The combination with a compressor having inlet and outlet valves; of a governor having a base mounted on said compressor above the inlet valve therefor, a iiuid pressure operated trigger pivotally mounted at one end and at one side of the base, a valve actuator pivotally mounted in opposed relation to the trigger at the other side of the base and in longitudinal alignment with said trigger, said actuator having connection with said inlet valve, a bellcrank shaped latch fulcrumed on said actuator and having one arm provided with upper and lower inclined surfaces spaced diierent distances from its fulcrum for alternate engagement with said trigger, the other arm of said latch extending substantially -vertically, and a coil spring connected to said other arm and to said actuator.

3. In combination with a compressor having inlet and outlet valves, a governor mounted upon the compressor and having a pressure operated trigger member, a pivoted valve actuator, a spring-pressed latch member directly pivoted on the actuator and engaged by the trigger member for retaining the actuator in either of two positions, a spring connected between the latch and actuator for biasing the latch against movement by the trigger, said latch including means for effectively increasing the force of said bias when the valve actuator is in a given position whereby to prevent unintended release of said latch due to vibration of the compressor.

4. In combination with a compressor having inlet and outlet valves, a pressure control de` the latch pivot, spring means urging the latch into engagement with the free end of the trigger,

means for moving the free end of said trigger across a line passing through the pivot points of the trigger and actuator in response to variations in the pressure to be controlled whereby the inclined faces of the latch are alternately engaged by the free end of the trigger member, the pivot point of the latch member being located laterally of the line passing through the pivot points of the trigger and actuator whereby the resistance to movement ofthe latch and actuator by said trigger is greater when the trigger is in engagement with the inclined face of the latch nearest the latch pivot.

5. In combination with a compressor having inlet and outlet valves, of a governor having a duid pressure operated trigger. an inlet valve actuator comprising an inverted U-shaped stamping pivoted at one end and serving to release the inlet valve or hold it in open position, a bell crank latch fulcrumed on the actuator and having one end provided with a .pair of inclined surfaces spaced different distances from its fulcrum for alternate engagement with said trigger to retain the actuator and inlet valve in either of their two positions, and spring means engaging the other end of the latch for retaining the first named end of the bell crank in contact with said I trigger whereby a greater degree of force is necessary to move the latch from the position in which the actuator holds the inlet valve in open position than is necessary to move the latch when theactuator is in its other position.

NIELS A. CHRISTENSEN. 

